1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention relates to a semiconductor device, a display device, an electronic device, a manufacturing method thereof, or a driving method thereof. One embodiment of the present invention particularly relates to, for example, a reflective liquid crystal display device.
Note that the term “display device” means a device including a display element. In addition, the display device includes a driver circuit for driving a plurality of pixels, and the like. Furthermore, the display device may include a control circuit, a power supply circuit, a signal generation circuit, or the like formed over another substrate.
2. Description of the Related Art
With the recent rapid spread of portable information terminals such as smartphones, improvement in their performance has progressed rapidly. Their screens have been increased in size and resolution, and some recent ones have resolutions as high as over 300 ppi.
For example, liquid crystal display devices generally have a structure in which R, G, and B sub-pixels are provided in a display region and provided with their respective color filters. The color filters are provided over a substrate (a counter substrate) which faces an active-matrix substrate (a substrate provided with elements (e.g., transistors) for driving pixels).
With the increase in resolution, the alignment accuracy between an active-matrix substrate and a counter substrate provided with color filters can be recognized as a problem. In view of this problem, attention has been focused on what is called a color filter on array (COA) structure, in which a color filter is formed on the active-matrix substrate side.
As a liquid crystal display device with a COA structure, a reflective or semi-transmissive liquid crystal display device which includes a color filter, a pixel electrode, and a reflective layer on the active-matrix substrate side and in which light entering from the counter substrate side is transmitted through the pixel electrode and the color filter and is reflected by the underlying reflective layer and is visually recognized is disclosed (e.g., see Patent Document 1 and Patent Document 2).